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Xerography printed Mendel

Posted by spacexula 
Xerography printed Mendel
May 28, 2010 10:48AM
Could someone please start a desktop laser printer printed Mendel Wiki page for me. Starting documentation of how to print Mendel using wax, a freezer, and a desktop laser printer.

Can't figure out where to put my documentation.

Re: Xerography printed Mendel
May 28, 2010 11:00AM

Am I doing it right?
Re: Xerography printed Mendel
May 28, 2010 11:52AM
Ok, file is attaching now, will post on blog the proccess tonight. But basically here is how it goes.

Use Pepakura to unfold Mendel parts to be printed.

Print as dark as possible and to scale using Pepakura using a laser printer.

Transfer printed design to fiberboard using an iron and steam.

Use razor to fold part.

Dampen part to make it harder when cold. Freeze part.

Make very hard parifin wax using Stearic acid.

Slowly add the wax to the paper model using meat injector.

Drill holes, use part.

These parts are less strong than Resin, but not nearly as prone to breakage. I will TRY to build a Mendel using these parts, and take you along for the ride (unless you outrun me)

Re: Xerography printed Mendel
June 02, 2010 12:25PM
Wouldn't pouring the hot wax end up undoing the freeze step? Maybe it will be more clear when you get some pictures.
Re: Xerography printed Mendel
June 02, 2010 10:02PM
The cooling causes the wax to change phase quicker, that way it doesn't leak. The more wax in the part, the more hot wax you can add without leaks. working on the next set of videos

Re: Xerography printed Mendel
June 07, 2010 06:33AM
Why not use epoxy resin and fibreglass?
Re: Xerography printed Mendel
June 07, 2010 12:52PM
Hot the vertexs done, happy with quality..

Ok reason for wax. It's non toxic, it's "fixable", it's cheap ($1 1-2lb), it's available world wide, it does not or contract much, it has no fumes, you can dial the firmness & melt temp with acid....

Re: Xerography printed Mendel
June 07, 2010 01:40PM
I have read of a material called "aluminum hard wax", that is sometimes used for testing of CNC machines, and can then be melted, formed into a new solid block, and machined again.
Re: Xerography printed Mendel
July 31, 2010 01:02AM
Yup, blue machinable wax is extremely common for prototyping, here's one supplier googled up at random:

Any place that supplies jewelers or machinists stocks it. smiling smiley

-Sebastien, RepRap.org library gnome.

Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything! grinning smiley
Re: Xerography printed Mendel
July 31, 2010 02:32AM
Here is a recipe for the stuff:

have been working on the Xerox Mendel for a bit, and I keep running into issues with the wax shrinking too much. I found out that I need to let the Wax cool down slower, which makes it leak out more. I am going to have to find a good balance.

Found this website: [www.machinablewaxes.com] they have a great description on how to make machinable wax at home. All you basically do is melt LDPE in a deep fat fryer full of paraffin wax. Basically you raise raise 4lb of paraffin wax to 95C for LDPE or 110C for HDPE. You then add 1 lb of LDPE or HDPE very slowly. Any amount can be made. Considering the limitations of a Maker bot drimel toolhead, this could be a great substrait.

The store this is from looks like it's dying, so I will quote it here:

"You may be looking for a cost effective solution for machinable wax.
One basic composition of machinable wax is simply standard parrafin wax, available at most craft stores, and polyethylene.
What is polyethylene? It’s most basic description is that it is a thermoplastic and it is derived from petroleum. The two main types are Low Density and High Density polyethylene, commonly referred to as LDPE and HDPE respectively. The following is a list of common LDPE/HDPE items:
* Grocery store bags
* Garbage Bags
* Paint drops (plastic sheets)
* Lawn Chairs
* Cutting Boards
* Plastic Lumber
* Milk Jugs
* Commercial Bathroom stalls
One of THE most common uses is in plastic grocery store bags. This is also probably the best source of LDPE/HPDE for use in making homemade machinable wax. It’s readily available as most people have 50 or so stuffed away in a pantry or cabinet. Perfect to make a little machinable wax with.
Alternate sources for use in a machinable wax recipe, would be plastic drop clothes used in painting. They can be purchased at most home improvement stores.
Most plastics are usually marked with LDPE or HDPE and have a number 4 or 2 (respectively) located on recyclable polyethylene.
In general it’s easier to melt down LDPE for use in machinable wax. LDPE has a lower melting point, and hence mixes better with the parrafin. LDPE’s melting point for continuous heat is 203F (95C). HDPE’s melting point with continuous heat is 230F(110C). It may be helpful to note that in general Target uses LDPE and Walmart uses HDPE.
What to use for melting??? You everyday kitchen cooker will work fine. It’s HIGHLY recommended that you dedicate a cooker to your machinable wax recipe. Temperature control that lists numbers is better than just lo/med/high. Do not use a double boiler, they generally only get up to 212F(97C). That’s only barely hot enough to melt LDPE, and it would take a lot longer.
So you have your block of candle wax, a few handfulls of grocery store bags, and a cooker. A METAL kitchen strainer will be very helpful as well. The large ones used for pasta noodles are best. You also need a mold to poor your machinable wax into. Use metal molds, plastic tupperware will melt or warp from the heat.
The general machinable wax recipe is a 4:1 ratio of parrafin wax to LDPE/HDPE. Your machinable wax recipe could vary depending on how hard or soft you want the wax to be. Obviously, the more plastic you add the harder it will get. But like sugar in a glass of tea, eventually the polyethylene will stop disolving and you will get large clumps of polyethylene form in the pot. If you poor it in a pan without straining it, it will look like goo in your wax and will not carve very well.
We will use a 4lb wax to 1lb LDPE in this machinable wax recipe example. So you will end up with about 5 lbs of machinable wax.
Start out by melting the wax in the pot. Get it good and hot, about 250-275F, max 275F.
Once you’ve reached temp, start feeding in small pieces of the plastic. If you can, cut up the plastic into small strips before feeding it in. It will melt better and more consistently than just dumping whole bags in. Stir constantly and use good ventilation.
You will know you’ve added enough because the plastic will stop melting as well. It will start balling up into clumps.
Now you can use the kitchen strainer, poor your wax through the strainer into your mold. This will remove any unwanted clumps from the mix.
For cooling, try to slow down the cooling as much as possible. You can wrap the mold with an old blanket, or use a small space heater to keep the area around the mold warm. Some warping is unavoidable. You can either plane the finished product, or use a CNC router to shave down the top.
You will be left with a good quality machinable wax. Refine your machinable wax recipe. You may try different types of wax, or different types of polyethylene in your recipe.

Re: Xerography printed Mendel
July 31, 2010 03:24AM
Do not use a double boiler, they generally only get up to 212F(97C).

hot smiley Oh, fuck me. hot smiley
Wax is the most dangerous stuff we can work with. Melts from the bottom up so it looks solid when it's molten, after which point it vaporizes then spontaneously combusts. Good way to take out your kitchen.

... I'd suggest using a double boiler.

-Sebastien, RepRap.org library gnome.

Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything! grinning smiley
Re: Xerography printed Mendel
July 31, 2010 10:03AM
BTW the Xerox Mendel died a fantastic death when one of my steppers got hot enough to melt the wax, wax went inside the stepper, and ignited. I lost my work bench, and had to replace the drywall above my work table.

Spacexula has a habit of suggesting very stupid and dangerous things.

Re: Xerography printed Mendel
July 31, 2010 10:15AM
I'd suggest following their suggestion, and using a temperature controlled vat.

You can buy a "deep fat fryer" which has a thermostat controlled heater in it, allowing you to control the temperature of your molten wax fairly precisely. You encounter the same sort of problems when doing deep fat frying, as fat/oil/wax is all pretty much the same stuff. Which is why people use thermostat-controlled fryers for making french fries. You're correct that cooking wax straight on the stovetop is a really bad idea, as you have no way of knowing how hot it really is. The predictable result is that it gets too hot. Since hot oil looks just like cold oil, the first indication you have that it's too hot is that it starts smoking, and the second when it bursts into flame. Deep fat frying is a well-understood process, and while more dangerous than other sorts of cooking, is successfully and fairly safely done in fast food restaurants around the world.

You CAN cook french fries in a cast iron skillet over a gas stove, but you have to be careful not to overheat the oil, which generally means keeping fries in it at all times. The water in the potatoes boils away, cooling the oil. Also, the appearance of the fries (rate of water boiling away, basically) gives you a rough idea of the temperature. Not a technique that will work for observing the temperature of a machinable wax mix winking smiley

Moral of the story: Cut your potatoes and do your other prep work before you get your oil hot, so you don't leave the oil empty while you hurry to cut more potatoes. (Been there, done that. Didn't catch fire, though!) And so you can devote enough of your attention to monitoring the temperature of your oil to make sure it doesn't end up too hot.

You could also go to a specialty cooking store and get a suitable thermometer. I don't recommend a candy thermometer, get a specialty deep fat frying thermometer, as it'll be more reliable, less breakable, and have a matching temperature range. But then you have to watch things more closely than you would with an automatic temperature controller, and it wouldn't cost that much more to just get a deep fat fryer anyway. Especially since you have to dedicate the cooker to wax anyway...

I think the comment about "It’s HIGHLY recommended that you dedicate a cooker to your machinable wax recipe." is funny. I know that I wouldn't like sweet and sour chicken that tastes like a parrafin/LDPE combo!

I'm building it with Baling Wire
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